1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index f8c28607ccd6..43cf60832468 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -49,6 +49,7 @@ static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 #endif
 static DEFINE_RWLOCK(cpufreq_driver_lock);
+static DEFINE_MUTEX(cpufreq_governor_lock);
 
 /*
  * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
@@ -1635,6 +1636,21 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 
         pr_debug("__cpufreq_governor for CPU %u, event %u\n",
                                                 policy->cpu, event);
+
+        mutex_lock(&cpufreq_governor_lock);
+        if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
+            (policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
+                mutex_unlock(&cpufreq_governor_lock);
+                return -EBUSY;
+        }
+
+        if (event == CPUFREQ_GOV_STOP)
+                policy->governor_enabled = false;
+        else if (event == CPUFREQ_GOV_START)
+                policy->governor_enabled = true;
+
+        mutex_unlock(&cpufreq_governor_lock);
+
         ret = policy->governor->governor(policy, event);
 
         if (!ret) {
@@ -1642,6 +1658,14 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
                         policy->governor->initialized++;
                 else if (event == CPUFREQ_GOV_POLICY_EXIT)
                         policy->governor->initialized--;
+        } else {
+                /* Restore original values */
+                mutex_lock(&cpufreq_governor_lock);
+                if (event == CPUFREQ_GOV_STOP)
+                        policy->governor_enabled = true;
+                else if (event == CPUFREQ_GOV_START)
+                        policy->governor_enabled = false;
+                mutex_unlock(&cpufreq_governor_lock);
         }
 
         /* we keep one module reference alive for